Posts from 2024

  • Cloning Proxmox with LVM Thin Pools

    During Black Friday last year, I got tempted by a super good offer of a dedicated server in Kansas City with the option of connecting it to the Kansas City Internet Exchange (KCIX). Here are the specs:

    • Intel Xeon E5-2620 v4 (8 cores, 16 threads)
    • 64 GB DDR4 RAM
    • 500 GB SSD
    • 1 Gbps unmetered bandwidth

    It was such the perfect thing for AS200351 (if a bit overkill), so I just had to take it. I set it up during the winter holidays, having decided to install Proxmox to run a bunch of virtual machines, and all was well. Except for one thing—the disk.

    You see, the server came with a fancy SAN, with exactly 500 GiB of storage mounted over iSCSI via 10 Gbps Ethernet, backed by a highly reliable ZFS volume (zvol). While this all sounds good on paper, in practice I am barely able to hit over 200 MB/s when doing I/O, even at large block sizes. Nothing I did seemed to help, so I asked the provider to switch it to physical drives.

    Having configured Proxmox just the way I wanted it, I opted against reinstalling it from scratch, instead choosing to clone the disk. The provider suggested using Clonezilla, which should be able to do this sort of disk cloning very quickly. So we found an agreeable time, took the server down, and booted Clonezilla over PXE. All should be good, right?

    As it turns out, this ended up being a super painful experience.

    Editorial note: This story is based on my memory and incomplete console output. While the broad story is correct, the commands provided may not be correct.

    (Read more...)